Damping Ratio of Foundation Bed with Multilayered Rubber-Soil Mixtures

In this paper, a series of plate load tests on a sandy soil bed containing multiple layers of granulated rubber-soil mixture (RSM) under incremental cyclic loading was performed. Incremental cyclic loading in five steps with amplitudes of 140, 280, 420, 560 and 700 kPa were applied to the loading plate to evaluate the settlement behavior and damping ratios of foundation bed. The results show that both the total and residual settlements of the loading plate decrease with increase in the number of RSM layers, regardless of the level of applied cyclic load, but the rate of reduction in both settlements reduces with increase in the number of RSM layers. There is also an appreciable improvement in the value of the damping capacity with increase in the number of RSM layers as the damping ratio increases by 4-5% beyond the value of 12-15% obtained on untreated sand. On the basis of the study, the concept of using multiple RSM layers not only is a very attractive material to achieve vibration attenuation for machine foundation and railway track beds, but also, the environmental impacts of waste tires are attenuated by using as composite materials in geotechnical applications